Power-Driven Global Routing for Multisupply Voltage Domains

Abstract EN

This work presents a method for global routing (GR) to minimize power associated with global nets.

We consider routing in designs with multiple supply voltages.

Level converters are added to nets that connect driver cells to sink cells of higher supply voltage and are modeled as additional terminals of the nets during GR.

Given an initial GR solution obtained with the objective of minimizing wirelength, we propose a GR method to detour nets to further save the power of global nets.

When detouring routes via this procedure, overflow is not increased, and the increase in wirelength is bounded.

The power saving opportunities include (1) reducing the area capacitance of the routes by detouring from the higher metal layers to the lower ones, (2) reducing the coupling capacitance between adjacent routes by distributing the congestion, and (3) considering different power weights for each segment of a routed net with level converters (to capture its corresponding supply voltage and activity factor).

We present a mathematical formulation to capture these power saving opportunities and solve it using integer programming techniques.

In our simulations, we show considerable saving in a power metric for GR, without any wirelength degradation.